I. Field of the Invention
In various types of high and low temperature arrangements used in chemical plants, refineries and similar types of industrial locations, a multitude of pipes, tanks and related equipment must be used as storage and conduit systems for the material or materials utilized in the various processes employed at the various locations mentioned. Often this equipment must carry and store fluids that range from cryogenic temperatures to 1400 degrees fahrenheit and which may also be caustic or corrosive in nature. Due to the nature of these fluids or gases, the equipment within which they are transported and stored must deploy various types of configurations of insulating material such as preformed links of insulation defining half cylinders which are clamped around the pipes, molded insulation formed or applied directly on or to the pipes or strips of insulation wrapped around the pipes. In order to ensure the integrity of the transportation and storage equipment such as pipes and vessels, periodic checks are necessary so as to determine whether or not there has been corrosion on the interior or exterior of the piping or equipment. Periodic checks of the thickness of the material also permit maintenance personnel to schedule replacement activities so that the unanticipated shut down of a system can be avoided. Of the methods used to determine and check structural integrity of the vessels and piping, a preferred procedure is to utilize ultrasonic testing equipment which will provide indication of the pipe or vessel wall thickness These types of devices utilize ultrasonic transducers which must be maintained in direct contact with the metal wall of the pipe or vessel subject to testing in order to make the appropriate measurements of thickness. Since, as noted above, the equipment which is being tested is normally insulated the insulating material must be removed in order for the test to be properly conducted. The presence of the insulating prevents such test activity. Following testing it is necessary to replace the insulation in order to maintain the insulation integrity of the system and avoid possible heat loss, gain and/or injury to workers.
In light of the need to have direct contact with the various pieces of equipment, thousands of dollars are often wasted annually in stripping, inspecting and then reinsulating this equipment. Often, various methods of ultrasonic inspection require the expensive removal and replacement of large sections of pipe jacketing and insulation. Even when only small holes are made, the exposed test points can easily end up as ragged, dangerous eyesores which allow substantial temperature loss. Further, moisture can enter at these points and wet the insulation and cause external pipe corrosion.
II. Description of the Prior Art:
Various types of demountable insulating plug configurations have been tried, however, none are presently available which provide all of the advantages of the present invention. Some of those various prior art devices are as follows:
U.S. Pat. No. 3,658,096 issued to Higuera discloses a plug formed of a "biscuit" of selected insulating material in desired shape secured to one flat surface of a cap which has substantially larger dimensions, the plug includes a handle which is integrally formed to certain locking tabs, each end of said handle extending through the cap and/or withdrawn when the handle is pulled and reinserted into the appropriate location when the handle is pushed
U.S. Pat. No. 3,827,462 issued to Celesta, discloses a plug which comprises a member for insertion into the hole, a cap integrally constructed with the member, a groove which extends across the cap, and a spring means which has a length greater than that of the groove and which can be placed into the groove when the plug is being utilized so as to engage the insulation with the two ends of the spring in order to retain the plug in the whole.
U.S. Pat. No. 4,091,842 issued to Greenawalt et al., discloses a resealable sealing assembly which utilizes a cylindrically shaped hollow plug with a concavely curved angular lip at the top of said plug which plug also has an angular cleat protruding outwardly from the side, and a hollowed sleeve which surrounds the plug which maintains contact with the insulation material and is bonded thereto.
U.S. Pat. No. 5,010,926 issued to Herman Kurth et al., discloses an insulation access aperture liner which simply serves the same purpose as the sleeve described and disclosed in the Greenawalt patent.
U.S. Pat. No. 5,014,866 issued to Moore, discloses an insulation seal which is essentially a plug and separate sleeve sealing assembly, again similar to that described and claimed in the Greenawalt patent. The sleeve assembly maintains contact with the insulation material and a plug which fits within that sleeve.
Applicants are also aware that substantially flat stoppers such as that which makes up the annular body portion of applicants' invention have been used for a multitude of purposes by the general public. However, applicants do not believe that such an item has been used as described and claimed herein as part of the overall invention overall which is the subject of this application.